
 /*
 *获取cookie
 */ 
 function getCookie(c_name){
	if (document.cookie.length>0){
	  c_start=document.cookie.indexOf(c_name + "=")
	  if (c_start!=-1){ 
		c_start=c_start + c_name.length+1 
		c_end=document.cookie.indexOf(";",c_start)
		if (c_end==-1) c_end=document.cookie.length
		return decodeURI(document.cookie.substring(c_start,c_end));
	  } 
	}
	return "";
 }
 /*
 *设置cookie
 */
  function setCookie(c_name,value,expiredays){
	 var exdate=new Date();
	 exdate.setDate(exdate.getDate()+expiredays);
	document.cookie=c_name+ "=" +encodeURI(value)+
	((expiredays==null) ? "" : ";expires="+exdate.toGMTString())+";path=/";
  }
  /*
  *删除cookie
  */
  function delCookie(name){
	var exp = new Date();
	exp.setTime(exp.getTime() - 1);
	var cval=getCookie(name);
	if(cval!=null)
	  document.cookie= name + "="+cval+";expires="+exp.toGMTString();
  }